Artillery casing



5, 1958 y G, RENOU Y2,845,865

' ARTILLERY CASING Filed Dec. 29. 1?::54

ARTILLERY CASDIG Georges Renon, Paris, France, assignor to Forges & Ateliers de Constructions Electriques de Jeumont, Paris, France, a French company Application December 29, 1954, Serial No. 478,356

Claims priority, application France January 5, 1954 4 Claims. (Cl. 102-43)l 'Ihe present invention relates to artillery shell cases and is more particularly concerned with an improved artillery shell case structure wherein means arevprovided for protecting the breech of the gun during firing of the shell.

In known shell casing constructions, the tubular casing wall is formed from sheet metal of trapezoidal outline which is rolled into a tube with an overlapping helicoidal outer joint. When a shell formed with such a casing is red, the VVery high pressure gases which are evolved at the moment of firing dilate the tubular portion ofV the shell casing and force it against the inside of the gun barrel and, spreading out along the helicoidal joint, attack the breech of the gun, which is undesirable.

To avoid this drawback, it has been proposed to provide adjacent the open outer end of the casing, a barrier to prevent the escape of gas along the joint, this barrier being' formed by chamfering the edge of rolled metal sheets. Such an arrangement is partially etfeetive in avoiding the leakage of gases but it has been found that it is more diicult to extract the casing after the shell has been red and one disadvantage has, therefore, given way to-another. I believe that this diiculty in removing the shell casing is probably due to the fact thatl the absence of gas between the casing andthe barrel makes the elastic contraction of the casing in a radial direction much more difficult. This expedient, therefore, is completely unsatisfactory with regard to the important problem of the extraction of fired shells, according to the results of ring tests.

It is the principal object of the present invention to provide a shell casing which avoids all of the disadvantages and drawbacks of 'prior constructions.

It is another object of the invention to provide a shell casing of the character indicated which not only fully protects the gun breech during tiring but also is easily extracted from the barrel after the shot has been fired.

In accordance withl the invention, there is provided in the exterior helicoidal joint of a shell casing formed from a rolled trapezoidal sheet of metal, a relatively short barrier adjacent the closed end or base of the casing. It is a feature of the construction of the invention that the barrier lies between the longitudinal mid-point of the Ishell casing, i. e. the point at which a plane perpendicular to and bisecting the axis of the casing intercepts the casing wall, and the closed end of the casing and is closer to the closed end or base of the casing than to the longitudinal mid-point of the casing body.

Other objects and features of the invention will be readily apparent from the following detailed description thereof and from the accompanying drawing wherein,

1 is a sectional view of a gun barrel showing in elevation therein a. shell casing in which are indicated the area in which the previously-proposed barrier has been placed and the location of the barrier in accordance with the lpresent invention;

Fig. 2 is a fragmentary elevational view of a shell 2,345,865 Patented Aug. V5, 1958 casing constructed in accordance with the invention;

Fig. 3 is a fragmentary sectional View on an enlarged scale, taken approximately along the line 3 3 ofk Fig. 2; and

Fig. 4 is a similar fragmentary sectional View taken approximately along the line 4 4 of Fig. 2.

Referring to the drawing and more particularly to Fig. 1, the reference numerals 1 and 2 indicate the two overlapping end portions of the trapezoidal sheet metal member which is rolled on itself to form the overlapping helicoidal outer joint 3, the sheet metal member 1, 2 being secured in any convenient way, as by crimping, to the metal base 4. The shell casing is received in the gun barrel 5, closed by the gun breech 6. In accordance with prior proposals, the helicoidal joint 3 has been provided with a barrier having the full length of the joint 3 or with a local barrier in the region indicated at 7, with the abovementioned disadvantages. In accordance with the present invention, a relatively short barrier is provided in the helicoidal joint in the region indicated at 8 with complete avoidance of the disadvantages of prior constructions. As shown in Fig. l, the barrier in the region 8 lies between the longitudinal mid-point a-a of the casing body and the bottom or base 4. Also, as shown in Fig. 1, the barrier in the region 8 is closer to the base 4 than to the longitudinal center line of the casing. In any event, the inner end of the barrier is only slightly spaced from the base 4. This space may vary but for best results it should not be more than about 20% of the length of the shell casing nor less than about 3% of the shell casing length. Advantageously, the distance between the inner end of the barrier and the base 4 is two to ten centimeters, for casings of 40 to 60 cm. size, for example.

The longitudinal length of the relatively short barrier may also vary but advantageously it has a length more than about 5% of the casing length but not more than about 30% of the casing length. In its preferred form, the barrier has a length of one to live centimeters. For example, in a casing of l0 cm. diameter, a barrier having a length of 40 mm. has been found to be particularly suitable.

As shown in Fig. 3 the helicoidal joint having no barrier comprises a gap or channel which normally occurs in the construction of the casing by overlapping the layers 1 and 2 of the sheet metal forming the casing body. This gap is substantially triangular in cross section. The barrier in accordance with the invention is provided by substantially completely filling in this triangular gap s0 that in the area of the barrier upon the external surface of the casing has a substantially continuousvarcuate outine, as shown in Fig. 4. The barrier is preferably formed as shown in Fig. 4, by means of a relatively short chamfer 9 formed on the inside surface of the portion 2 of the sheet metal so that this portion will overlie the portion 1, the chamfer being formed by known metal working llrCaIlS.

Shell casings constructed in accordance with the present invention have been found to protect the gun breech from attack by gases evolved upon firing of the shell and at the same time to prevent jamming of the casing in the gun barrel so that the casing can be easily and readily removed from the barrel after the shot has been discharged. There is thus provided, in accordance with the invention, a shell casing structure which avoids the disadvantages and drawbacks of prior constructions.

It will be understood that changes and modifications may be made in the embodiments of the invention abovedescribed and illustrated in the drawing without departing from the scope of the invention, as dened in the appended claims, and it is intended therefore that all matter conp present A 12,845,865 A Y- tained in the foregoing description and in the drawing shall be interpreted as illustrative only.

What I claim and desire to secure by Letters Patent is:

l. A shell casing having a body formed by a rolled. sheet metal member having overlapping edges defining an outer joint deiining a channel in the exterior surface of said body, a base secured to said body, and scaling means for said joint comprising a charnfer occupying a portion only of said joint, said chamfer having a length equal to 5% to 30% of the casing length and being disposed in said joint between the base and the vertical mid-point of said joint, the portion of said channel lying between said chamfer and the end of said casing opposite said base providing for gas entrance from said end to said charnfer.

2. A shell casing having a body formed by rolled sheet metal member having overlapping edges defining an outer joint defining a channel in the exterior surface of said body, a base secured to said body and sealing means for said joint comprising a charnfer occupying a portion only of said joint, said charnfer having a length equal to 5% to 30% of the casing length and being disposed between the base and the vertical mid-point of said joint, and said chamfer being spaced from the base by a distance equal to 3% to 20% of the casing length, the portion of said channel lying between said charnfer and the end of said casing opposite said base providing for gas entrance from said end to said charnfer.

3. A shell casing having a body formed by a rolled sheet metal member having overlapping edges dening an outer joint dening a channel in the exterior surface of said body, a base secured to said body, and sealing means for said joint comprising a barrier occupying a portion only of said joint, said barrier having a length equal to 5% to 30% of the casing length and being disposed in said joint between the base and the vertical mid-point of said joint, the portion of said channel lying between said charnfer and the end of said casing opposite said base provid for gas entrance from said end to said chamfer.

d. A shell casing having a body formed by a rolled sheet metal member having overlapping edges defining an outer joint defining a channel in the exterior surface o? said body, a base secured to said body and sealing ,is l'or said joint comprising a barrier occupying a portion only of said joint, said barrier having a length equal to 5% to 36% of the casing length and being disposed between the base and the vertical mid-point of said joint, and said barrier being spaced from the base by a distance equal to 3% to 20% of the casing length, the portion of said channel lying between said chamfer and the end of said casing opposite said base providing for gas entrance from said end to said charnfer.

References Cited in the rile of this patent FOREIGN PATENTS Germany May 12, 1919 Germany June 7, 1943 

